Buggy code:
public BaseWicketTester ( final WebApplication application , final ServletContext servletCtx ) { } protected IPageManagerProvider newTestPageManagerProvider ( ) { } public Page getLastRenderedPage ( ) { } private void setupNextRequestCycle ( ) { } protected Response newServletWebResponse ( final ServletWebRequest servletWebRequest ) { } private ServletWebRequest newServletWebRequest ( ) { } private void newSession ( ) { } public MockHttpServletRequest getRequest ( ) { } public void setRequest ( final MockHttpServletRequest request ) { } public Session getSession ( ) { } public MockHttpSession getHttpSession ( ) { } public WebApplication getApplication ( ) { } public ServletContext getServletContext ( ) { } public void destroy ( ) { } public boolean processRequest ( ) { } public boolean processRequest ( final MockHttpServletRequest request ) { } public boolean processRequest ( final MockHttpServletRequest request , final IRequestHandler forcedRequestHandler ) { } public boolean processRequest ( final IRequestHandler forcedRequestHandler ) { } private boolean processRequest ( final MockHttpServletRequest forcedRequest , final IRequestHandler forcedRequestHandler , final boolean redirect ) { } private void recordRequestResponse ( ) { } public Page startPage ( final IPageProvider pageProvider ) { } public Page startPage ( final Page page ) { } public ResourceReference startResource ( final IResource resource ) { } public ResourceReference startResourceReference ( final ResourceReference reference ) { } public ResourceReference startResourceReference ( final ResourceReference reference , final PageParameters pageParameters ) { } public MockHttpServletResponse getLastResponse ( ) { } public String getLastResponseAsString ( ) { } public String getWicketAjaxBaseUrlEncodedInLastResponse ( ) throws IOException , ParseException , ResourceStreamNotFoundException { } public List < MockHttpServletRequest > getPreviousRequests ( ) { } public List < MockHttpServletResponse > getPreviousResponses ( ) { } public void setFollowRedirects ( boolean followRedirects ) { } public boolean isFollowRedirects ( ) { } public Url urlFor ( final IRequestHandler handler ) { } public String urlFor ( Link < ? > link ) { } @ Deprecated public final Page startPage ( final ITestPageSource testPageSource ) { } public void executeListener ( final Component component , final RequestListenerInterface listener ) { } public void executeListener ( final Component component ) { } public void executeBehavior ( final AbstractAjaxBehavior behavior ) { } public Url urlFor ( final AjaxLink < ? > link ) { } public void executeAjaxUrl ( final Url url ) { } public final < C extends Page > C startPage ( final Class < C > pageClass ) { } @ SuppressWarnings ( "unchecked" ) public final < C extends Page > C startPage ( final Class < C > pageClass , final PageParameters parameters ) { } public FormTester newFormTester ( final String path ) { } public FormTester newFormTester ( final String path , final boolean fillBlankString ) { } @ Deprecated public final Panel startPanel ( final ITestPanelSource testPanelSource ) { } public final < C extends Panel > Panel startPanel ( final Class < C > panelClass ) { } public final Component startComponent ( final Class < ? extends Component > componentClass , final IMarkupFragment pageMarkup ) { } public final Component startComponent ( final Component component , IMarkupFragment pageMarkup ) { } public void startComponent ( final Component component ) { } public Component getComponentFromLastRenderedPage ( String path , final boolean wantVisibleInHierarchy ) { } public Component getComponentFromLastRenderedPage ( String path ) { } public Result hasLabel ( String path , String expectedLabelText ) { } public < C extends Component > Result isComponent ( String path , Class < C > expectedComponentClass ) { } public Result isVisible ( final String path ) { } public Result isInvisible ( final String path ) { } public Result isEnabled ( final String path ) { } public Result isDisabled ( final String path ) { } public Result isRequired ( String path ) { } public Result isRequired ( FormComponent < ? > component ) { } public Result ifContains ( String pattern ) { <START_BUG> return isTrue ( ( ( ( "pattern<seq2seq4repair_space>'" + pattern ) + "\'<seq2seq4repair_space>not<seq2seq4repair_space>found<seq2seq4repair_space>in:\n" ) + ( getLastResponseAsString ( ) ) ) , getLastResponseAsString ( ) . toString ( ) . matches ( ( ( "(?s).*" + pattern ) + ".*" ) ) ) ; <END_BUG> } public void assertListView ( String path , List < ? > expectedList ) { } public void clickLink ( String path ) { } public void clickLink ( String path , boolean isAjax ) { } public void submitForm ( Form < ? > form ) { } public void submitForm ( String path ) { } private Url transform ( final Url url ) { } public < C extends Page > Result isRenderedPage ( Class < C > expectedRenderedPageClass ) { } public void assertResultPage ( final Class < ? > pageClass , final String filename ) throws Exception { } public Result isResultPage ( final String expectedDocument ) throws Exception { } public Result hasNoErrorMessage ( ) { } public Result hasNoInfoMessage ( ) { } public List < Serializable > getMessages ( final int level ) { } public void dumpPage ( ) { } public void debugComponentTrees ( ) { } public void debugComponentTrees ( String filter ) { } public Result isComponentOnAjaxResponse ( final Component component ) { } public void executeAjaxEvent ( final String componentPath , final String event ) { } public void executeAllTimerBehaviors ( final MarkupContainer container ) { } public void executeAjaxEvent ( final Component component , final String event ) { } public TagTester getTagByWicketId ( String wicketId ) { } public List < TagTester > getTagsByWicketId ( String wicketId ) { } public TagTester getTagById ( String id ) { } private void submitAjaxFormSubmitBehavior ( final Component component , AjaxFormSubmitBehavior behavior ) { } private void serializeFormToRequest ( final Form < ? > form ) { } public String getContentTypeFromResponseHeader ( ) { } public int getContentLengthFromResponseHeader ( ) { } public String getLastModifiedFromResponseHeader ( ) { } public String getContentDispositionFromResponseHeader ( ) { }

Fix:
return isTrue ( ( ( ( "pattern<seq2seq4repair_space>'" + pattern ) + "\'<seq2seq4repair_space>not<seq2seq4repair_space>found<seq2seq4repair_space>in:\n" ) + ( getLastResponseAsString ( ) ) ) , getLastResponseAsString ( ) . matches ( ( ( "(?s).*" + pattern ) + ".*" ) ) ) ;